A method of measurement of the energy of electrons extracted from the VEPP-4M accelerator is described. The method was verified experimentally. The results obtained are in good agreement with simulation. The energy resolution is 1.8% for electron energy of 1000 MeV and improves to 0.7% for electron energy of 3500 MeV.

Proton electromagnetic form factors are among the most important sources of information about the internal structure of the proton. Two different methods for measuring these form factors, the method proposed by Rosenbluth and the polarization-transfer method, yield contradictory results. It is assumed that this contradiction can be removed upon taking into account the hard part of the contribution of two-photon exchange to the cross section for elastic electron-proton scattering. This contribution can measured experimentally via a precision comparison of the cross sections for the elastic scattering of positrons and electrons on protons. Such a measurement, performed at the VEPP-3 storage ring in Novosibirsk at the beam energies of 1.6 and 1.0 GeV for positron (electron) scattering angles in the ranges of θ e = 15°–25° and 55°–75° in the first case and in the range of θ e = 65°–105° in the second case is described in the present article. Preliminary results of this experiment and their comparison with theoretical predictions are described.

We describe a precise measurement of the ratio of the ( e + p ) to ( e − p ) elastic scattering cross sections. This comparison is sensitive to the effect of two-photon exchange contributions which may be the cause for inconsistent extractions of the proton form factors obtained using different methods. The experiment was performed at storage ring VEPP–3, Novosibirsk at energies of positron/electron beams of 1.0 and 1.6 GeV with electron/positron scattering angles θ = 65÷105° for the first case and 15÷25° and 55÷75° for the second case. Details of the experiment and the preliminary results are presented.

The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of CO laser photons on the electron beam is used. The relative systematic uncertainty of the beam energy determination is estimated as 6 x 10(-5). It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods. (C) 2014 Elsevier B.V. All rights reserved.

To high precision measurement of Upsilon-meson masses with KEDR detector on VEPP-4M collider the beam energy calibration is needed. The project of laser polarimeter for beam energy measurement by resonance depolarization method is discussed. The polarization measurement is based on up-down asymmetry of Compton backscatterring of circular polarized photons on vertical polarized electrons. Scattered photons are registered by two-coordinate detector based on Gas Electron Multiplier. Expected effect is about 1.6% with 10 sigma confidence level.

The beam energy measurement system (BEMS) for the upgraded Beijing electron-positron collider BEPC-II is described. The system is based on measuring the energies of Compton back-scattered photons. The relative systematic uncertainty of the electron and positron beam energy determination is estimated as 2 x 10(-5). The relative uncertainty of the beam's energy spread is about 6%. (C) 2011 Elsevier B.V. All rights reserved.

The BEPC-II collider beam energy calibration system is discussed. The system is based on the Compton backscattering method. The expected precision of the electron and positron beam energy epsilon determination is delta epsilon/epsilon approximate to 3 . 10(-5).